Can this AGW hypothesis be proven?

At the 93% confidence interval the first part already has been proven - it's the quote from Phil Jones that deniers always take out of context.

As for the second part, yes it can be strongly supported. All that has to happen is for global temperatures to rise in the 2-5 degree range and for significant disruptions to natural and human systems to occur.

Lacking any alternative driver to climate other than CO2, it would be the obvious conclusion to draw.

Can the hypothesis be proven? Please take this from a neutral position. I am only going to state what the science tells us.

"Human actions ... leading to significant climate alterations" - this at the moment is suggested to be highly likely based on scientific evidence. Therefore it would be concluded that "current research and data suggests that humans are significantly influencing the global climate". Technically not "proven" but the data concludes that that part of the hypothesis is supported.

No matter if you agree AGW is real or not, the conclusion stated above will be drawn.

"signficant rise in average temperatures of the atmosphere, near surface and oceans" - a value for "significant" would have to be determined to draw any conclusions. Data and research largely agrees with that hypothesis. Therefore it would be concluded that "current reserach and data shows that average temperatures of the atmosphere and near the surface have risen at a trend not previously recorded or documented". I am unsure about ocean temps. If humans are causing this rising trend can not be "proven" but no known natural variables have been able to explain the trends observed.

Again if you are for or against AGW, the conclusion above will be drawn from the data available irrespectively.

"This rise ... will cause significant disruptions ... if unchekced". This part of the hypothesis assumes that a rise will occur (the data suggests that this assumption is a likely scenairo , only time will "prove" it or not). If it is assumed that the temperatures will rise, it would be quite safe to hypothese the disruptions. The impacts of climatic variability and factors has been measured and observed in the past. The potential impacts from similar climatic variability and factors would be assumed to be similar to past impacts if nothing is changed. (E.g. a heat wave kills X people in London, if nothing is done to mitigate or manage the impact of future heat waves it would be accepted that X people would die in the future). Ultimately though, it will only be proven if "nothing" is done ... bit late to help any one or thing after the fact. It is called risk management (or you may know it more colloquially as insurance).

wildman

"The hypothesis will only be proven when it comes true. That's the nature of the scientific method. The proof will be that global temperatures rise by 2-5 degrees C in this century."

In other words, given that a positive result for the hypothesis would result in millions of deaths, any real certainty about AGW should be regarded as forbidden knowledge. We must reduce our greenhouse gas emissions so that we never prove the hypothesis that humans are causing dangerous global warming.

seebob

"predictions are cheap"

Human lives aren't.

The hypothesis will only be proven when it comes true. That's the nature of the scientific method. The proof will be that global temperatures rise by 2-5 degees C in this century.

What we have now is a broad consensus (or not) among climate scientists that this hypothesis will come true and drastic action is needed now to avert the impending disaster.

Current empirical evidence, however, is not supporting the hypothesis. Ocean temperature as measured by the Argo buoy system shows no increase, but a slight decrease.

http://joannenova.com.au/2010/10/is-the-western-cl...

This is quite significant because the oceans hold 80%-90% of terrestrial heat. Atmospheric temperatures are rising, but the rate of increase is nothing to be alarmed about- if you look at UAH data here:

http://wattsupwiththat.com/widget/

Other temperature sources paint a more alarming picture. And sea levels seem to be increasing as well, but again the RATE of increase is falling off, contrary to what you would expect if the AGW hypothesis was correct.

http://wattsupwiththat.com/2011/03/28/bombshell-co...

Note to Kool-aid drinkers: This paper was published in a peer reviewed publication, not a right wing blog. And yes, there is a link to the paper itself in the above link.

I know there is some current empirical data supporting the hypothsis. I also know there is research contradicting the sea level findings. My point is, all it takes is one piece of contradictory data to falsify a hypothesis. Furthermore, if there is such disagreement over the magnitude of the current warming trend or sea level rise, how can we possibly make predictions about the future?

Proving it convincingly requires a level of science clearly well beyond your capabilities, so you can choose to believe either the world's top scientists (see below) or those, like the Republican members of the U.S. Congress, who are not scientists at all, but active liars about climate science.

You could, however, help test the "hypothesis" that smoking causes cancer. Start smoking three packs a day now, and check back with us in thirty years. But, kindly don't insist that we all smoke three packs a day too just to satisfy "skepticism" or alarmist paranoia about taxes causing Stalinism.

U.S. National Academy of Sciences, 2010:

http://books.nap.edu/openbook.php?record_id=12782&...

“Climate change is occurring, is caused largely by human activities, and poses significant risks for a broad range of human and natural systems.”

http://nationalacademies.org/morenews/20100716.htm...

“Choices made now about carbon dioxide emissions reductions will affect climate change impacts experienced not just over the next few decades but also in coming centuries and millennia…Because CO2 in the atmosphere is long lived, it can effectively lock the Earth and future generations into a range of impacts, some of which could become very severe.”

http://www.nasonline.org/site/PageServer?pagename=...

“The Academy membership is composed of approximately 2,100 members and 380 foreign associates, of whom nearly 200 have won Nobel Prizes. Members and foreign associates of the Academy are elected in recognition of their distinguished and continuing achievements in original research; election to the Academy is considered one of the highest honors that can be accorded a scientist or engineer.”

Predictability is a requirement of science. When certain circumstances occur, there is a predictable result.

"Climate scientists" claim to be scientists, and claim that AGW is a "scientific conclusion" but as their predictions fail even more often than chance, they have certainly done more to disprove the theory than prove it.

Sure can, wait about 500 years and see what happens. We should have plenty of evidence by then, either proving or disproving it.

I'll throw a few things at you. Just pulled from one source, it's late, I'm sick, and I have finite tolerance for fighting for science at this point.

We are contributing CO2 to the atmosphere: http://www.skepticalscience.com/human-co2-smaller-... and http://www.skepticalscience.com/co2-levels-airborn...

CO2 increases the average temperature of the biosphere: http://www.skepticalscience.com/exponential-increa...

The biosphere is, in consequence, warming: http://www.skepticalscience.com/Earth-expected-glo... , and will warm further: http://www.skepticalscience.com/climate-sensitivit... (I may have been a bit wrong about the rate, I think that's warming of 2-5 degrees total, not *necessarily* 2-5 degrees over the next century)

And, if we don't stop it, it http://www.skepticalscience.com/ocean-acidificatio... will http://www.skepticalscience.com/Can-animals-and-pl... do http://www.skepticalscience.com/sea-level-rise-pre... bad http://www.skepticalscience.com/few-degrees-global... things http://www.skepticalscience.com/global-warming-pos... .

edit:

The post this hypothesis was originally in got deleted for violating the question and answer format, somehow, so I'm glad I posted all this here, not there.

and re: "You omit to point out that the line is preceded by this caveat. “…place high or very high confidence in the following findings:” They don’t say it IS so, they say it is very likely."

Scientists talk like that. Virtually nothing is *absolutely* certain. Particularly when you're talking about something as chaotic and with as many factors and inputs as the average global climate. It could be that a massive chain of volcanic eruptions or a well-placed asteroid strike will negate all the warming we have generated to date (volcanic eruptions tend to cool, not warm the biosphere; ejecta from an asteroid could do the same). It could be that some unforeseen negative feedback will halt warming in its tracks. It could be that some rogue planet will come through the solar system and pull us out of our orbit, or smack into us and kill us all. There's a lot of possibilities, but the likeliest with the available evidence is, well, global warming, caused by us.

Absolutely can not be proven. 0.74 ± 0.18 °C Over 120 years the temperature has not even risen a whole one degree celsius. Of that 0.74, no one seems willing or able to say how much was man and how much was nature.

With AGW, you start with a simple fact, like Co2 can trap heat. You then wrap a monumental lie around that simple fact, and just point to it when anyone wants to argue.

2-5 degrees per century... I think we are falling behind. Unless that 0.74 ± 0.18 °C was all man... then we are still behind.

It is mere speculation...yet the AGW proponents state it with unwavering conviction.

Possibly, in 50...100 years they may be proved correct...or then again...maybe they won't.

Anyone can make predictions,predictions are cheap.